Estranged brothers Rahul and Arjun Kapoor (Fawad Khan and Sidharth Malhotra) are forced to come together and return to their childhood home in Coonor when their 90-year-old Dadu (Rishi Kapoor) suffers from a heart attack. Their parents, Harsh and Sunita Kapoor (Rajat Kapoor and Ratna Pathak) also live reside here. Rahul is a writer, who personifies the image of successful young man who appears to be the most mature person in the family. On the other hand, Arjun struggles to make it big as a writer and resorts to running a website and works part time as a bartender to make ends meet. Rahul is loved more by his parents for being more mature and successful. This doesn''t go well with Arjun. While the brothers struggle to get along, the parents, Harsh and Sunita Kapoor too are troubled with their own marriage. Harsh is discouraging of Sunita''s wish to open a catering business.
The brothers visit their Dadu, who is now placed in an ICU. To receive treatment, Dadu needs to be sent to Bangalore. When the issue of money arises, Sunita brings up Harsh''s old affair which proves to be an existing problem in their relationship. When Arjun intervenes, Rahul belittles his presence and they fight. While living under one roof, family secrets unravel and misunderstandings are on the verge of turning into tragedy. Dadu however doesn''t want to go to Bangalore and has just two wishes to fulfill. His first wish to be buried in an army burial with his old friends. His second wish is to take a family photo titled Kapoor & Sons - since 1921.
Arjun is reunited with his old friend Wasim, who invites him to a party and there he meets the lively Tia Singh (Alia Bhatt). After a misunderstanding, Arjun and Tia hit it off and later party together. Rahul visits an old property which he wants to purchase to use as an art studio. The property happens to belong to Tia, given to her by her late parents. Tia finds Rahul attractive and they later go out for dinner. However Rahul doesn''t reciprocate Tia''s feelings as she spontaneously kisses him. Tia reveals to Arjun that she lost her parents at the age of thirteen and lives alone. Arjun too reveals that Rahul''s bestseller novel''s idea was similar to his but he never confronted his brother so as to not break the family apart. Later Tia confesses to liking Arjun but regrets involving herself with Rahul unnecessarily.
Dadu is discharged and the Kapoor family throw a party to celebrate his birthday. Arjun invites Tia and discovers that she and Rahul already know each other. Arjun fears that Rahul and Tia have something between them but Rahul clarifies him that he is not interested in her. The party goes on well but problems arise when the family find out that Harsh has invited Anu, whom he had an affair with. Sunita acts out and a fight ensues between her and Harsh causing the party to end. Dadu brings the family together and takes a family photo of the four of them, temporarily uniting them. After the Kapoor